* Solution: A solution is a homogeneous mixture where one substance (the solute) dissolves evenly into another substance (the solvent).

* Compound: A compound is formed when two or more elements chemically combine in a fixed ratio.

In the case of sugar and water:

* Sugar dissolves in water. The sugar molecules distribute evenly throughout the water, creating a uniform mixture. You can't see separate sugar particles.

* The chemical composition of sugar and water remains unchanged. They don't chemically react to form a new substance.

Key difference: You can separate the sugar from the water through evaporation (heating), while a compound would require a chemical reaction to separate its components.